JPH05320473A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition improved in heat resistance, impact resistance and mechanical properties by mixing a specified heat- resistant copolymer with a specified graft copolymer. CONSTITUTION:This resin composition comprises 30-80 pts.wt. heat-resistant copolymer comprising 1-45wt.% N-substituted maleimide monomer (A), 5-40wt.% vinyl cyanide monomer (B) and 20-80wt.% aromatic vinyl monomer and/or alpha,beta-unsaturated carboxylic ester monomer (C) and having a reduced viscosity of 0.4-0.8dl/g and 70-20 pts.wt. graft copolymer obtained by grafting 70-25 pts.wt. monomer mixture comprising 10-70wt.% component B and 90-30wt.% component C onto 30-75 pts.wt. rubbery polymer (D), satisfying the relationship: 0.35y<=(x-z)<=0.90y [wherein (x) is the amount (wt. %) of component B, (y) is the amount (wt. %) of component A in the heat-resistant copolymer; and (z) is the amount (wt.%) of component B in the heat-resistant copolymer] and having a grafting ratio of 25-70% and a reduced viscosity of acetone-solubles of 0.45-1.0dl/g.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition having excellent heat resistance. More specifically, it has high heat resistance,
The present invention also relates to a thermoplastic resin composition which is excellent in impact resistance and mechanical properties and is suitable as a material for automobile interior parts, office supplies, parts for electric and electronic devices and the like.

[0002]

2. Description of the Related Art Recently, in the fields of automobiles, office products, electric appliances, etc., it has been attempted to make a part of a sheet metal into a resin for the purpose of weight reduction, energy saving and cost reduction. Attempts have been made to replace the alloy of polycarbonate and ABS resin with a heat and impact resistant resin such as modified PPE.

By the way, ABS resin is a thermoplastic resin having excellent chemical resistance and high mechanical strength.
Although it is widely used as a molding material, it has a drawback that it is unsuitable for use at high temperatures because of its poor heat resistance.

As a method of improving the heat resistance of this ABS resin, a method of introducing an N-arylmaleimide unit into the molecular chain of a copolymer of acrylonitrile and styrene has been proposed.

Maleimide copolymers are excellent in heat resistance and thermal decomposition resistance, but are extremely inferior in impact resistance and workability. Therefore, a composition having improved impact resistance by polymerizing maleimide with another vinyl compound in the presence of a rubbery polymer, or by mixing a maleimide-based copolymer with a graft polymer of rubber and a vinyl compound. Have been proposed (JP-A-57-167341 and JP-A-58).
-206657, JP-A-59-11322).

On the other hand, a composition having improved processability by mixing a maleimide copolymer with a styrene-acrylonitrile copolymer has also been proposed (JP-A-58).
-217535 and JP-A-58-217537).

Further, the impact resistance of the maleimide-based copolymer,
A method of mixing a specific graft copolymer and a specific maleimide-based copolymer for the purpose of improving moldability has been proposed (Japanese Patent Laid-Open No. 61-101547).

[0008]

However, JP-A-57-57
In 167341, JP-A-58-206657 and JP-A-59-11322, although the heat resistance is improved, the impact resistance and the moldability are insufficient. JP 58-217535 A and JP 58
Also in the description of JP-A-217537, the heat resistance and molding processability are improved, but the impact resistance is insufficient.
In JP-A-61-101547, the heat resistance and molding processability are improved by defining the weight average particle diameter of the graft rubber, the graft ratio, and the intrinsic viscosity of the ungrafted polymer contained in the graft polymer. However, the impact resistance is still not sufficient.

As described above, although the methods generally proposed so far have some improvement in heat resistance, mechanical properties, moldability, etc., the impact resistance represented by the Izod impact value and the falling weight impact value can be improved. The improvement is still inadequate and the applications are currently limited.

Under the circumstances described above, the present inventors have diligently studied a maleimide heat-resistant resin composition, and as a result,
The present inventors have found that by blending a maleimide heat-resistant copolymer with a specific graft rubber component in a specific ratio, it is possible to achieve high impact resistance and mechanical properties while maintaining high heat resistance, and arrived at the present invention.

[0011]

That is, the present invention is based on N-
Substituted maleimide monomer (A) 1 to 45% by weight, vinyl cyanide monomer (B) 5 to 40% by weight, aromatic vinyl monomer and / or α, β-unsaturated carboxylic acid ester monomer (C) composed of 20 to 80% by weight and having a reduced viscosity of 0.
4 to 0.8 dl / g heat resistant copolymer (A) 30 to
10 parts by weight of vinyl cyanide monomer (B) in the presence of 80 parts by weight and 30 to 75 parts by weight of rubbery polymer (D).
And an aromatic vinyl monomer and / or an α, β-unsaturated carboxylic acid ester monomer (C), obtained by graft-polymerizing 70 to 25 parts by weight of a monomer mixture consisting of 90 to 30% by weight, When the component (B) is x% by weight, the component (A) of the heat resistant copolymer (a) is y% by weight, and the component (B) is z% by weight, the composition difference (x−
z) is in the range of compositions satisfying the following formula (I): 0.35 × y ≦ (x−z) ≦ 0.90 × y (I), and the graft ratio is 25.
~ 70% range, the reduced viscosity of the acetone-soluble component is 0.4
The present invention provides a thermoplastic resin composition containing 70 to 20 parts by weight of a graft copolymer (b) in the range of 5 to 1.0 dl / g.

The present invention will be described in detail below.

Specific examples of the N-substituted maleimide monomer (A) of the heat-resistant copolymer (a) include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-iso-propylmaleimide. , N-butylmaleimide, N-alkylmaleimide such as Nt-butylmaleimide, N-cycloalkylmaleimide, N-cycloalkylmaleimide such as N-cyclodecanylmaleimide, N-phenylmaleimide, N-o-chlorophenylmaleimide and Examples thereof include N-arylene maleimides such as substitution products thereof. Preferably, N-phenylmaleimide is used.

Specific examples of the vinyl cyanide monomer (B) of the heat-resistant copolymer (a) include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is preferably used.

Specific examples of the aromatic vinyl monomer (C) of the heat-resistant copolymer (a) include styrene, α-methylstyrene, p-methylstyrene and pt-butylstyrene. You can Styrene and /
Alternatively, α-methylstyrene is preferably used.

Specific examples of the α, β-unsaturated carboxylic acid ester monomer (C) of the heat-resistant copolymer (a) include methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate and methacrylic acid. Examples thereof include cyclohexyl acid, and of these, methyl methacrylate is preferably used.

N-substituted maleimide monomer (A), vinyl cyanide monomer (B), which constitutes the heat-resistant copolymer (a),
The copolymerization composition ratio of the aromatic vinyl monomer and / or the α, β-unsaturated carboxylic acid ester monomer (C) is
(A) 1 to 45% by weight, (B) 5 to 40% by weight, (C)
20 to 80% by weight, preferably (A) 5 to 40
% By weight, (B) 10 to 30% by weight, and (C) 40 to 60% by weight. When the amount of the monomer (A) is less than 1% by weight, the heat resistance is insufficient, and when it exceeds 45% by weight, the impact resistance is significantly lowered. If the amount of the monomer (B) is less than 5% by weight, the impact resistance is insufficient, and if it exceeds 40% by weight, the heat coloring of the resin becomes large. If the amount of the monomer (C) is less than 20% by weight, the molding processability will be lowered, and if it exceeds 80% by weight, the impact resistance will be lowered, which is not preferable.

The method for producing the heat-resistant copolymer (a) is not particularly limited, and it can be produced by ordinary emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization or bulk-suspension polymerization.
Of these, emulsion polymerization is preferred.

Examples of the rubbery polymer (D) of the graft copolymer (B) include polyene (PBD), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and other diene rubbers, ethylene. Examples include olefin rubbers such as propylene rubber (EPR) and ethylene-propylene-conjugated diene rubber (EPDM), and acrylic rubbers such as polybutyl acrylate. Of these, PBD is particularly preferable.

Specific examples of the vinyl cyanide monomer of the graft copolymer (b) include acrylonitrile and methacrylonitrile. Of these, acrylonitrile is preferred.

Specific examples of the aromatic vinyl monomer (C) of the graft copolymer (B) include styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene and the like. it can. Of these, styrene and / or α-methylstyrene is preferable.

Specific examples of the α, β-unsaturated carboxylic acid ester monomer (C) of the graft copolymer (B) include methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate and methacrylic acid. Examples thereof include cyclohexyl and the like, and of these, methyl methacrylate is preferable.

Amount of rubbery polymer (D) constituting the graft copolymer (B), vinyl cyanide monomer (B), aromatic vinyl monomer and / or α, β-unsaturated carvone. The copolymer composition of the acid ester-based monomer (C) is (D) 3
0-75 parts by weight, (B) 10-70% by weight, (C) 90
Is 30 to 30% by weight, preferably (D) 40 to 60 parts by weight, (B) 20 to 60 parts by weight, and (C) 80 to 40 parts by weight.

As an essential condition of this patent, the component (B) of the graft copolymer (b) is x% by weight, the component (A) of the heat resistant copolymer (1) is y% by weight, and the component (B) is When the component is defined as z% by weight, the composition difference (xz) of the component (B) satisfies the following formula (I): 0.35 × y ≦ (xz) ≦ 0.90 × y (I) There is a need to.

Preferably 0.38 × y ≦ (xz) ≦
The range is 0.85 × y, and more preferably 0.40.
The range is xy ≦ (x−z) ≦ 0.75 × y. (X-
When z) exceeds the range of the formula (I), the compatibility between the graft component and the matrix phase is lowered, and the impact strength is largely lowered, which is not preferable.

There is no particular limitation on the method for producing the graft copolymer (b), and the conventional graft polymerization may be used for AB.
Any method can be selected and used from the methods commonly used for producing S resins, such as emulsion polymerization, bulk polymerization, and bulk suspension polymerization.

The graft ratio of the graft copolymer (2) is
25 to 70%. If the graft ratio is less than 25%, the impact strength is largely decreased, and if it exceeds 70%, the impact strength, especially the Izod impact strength is significantly decreased, which is not preferable.

Here, the graft ratio means a graft ratio (%).
= (Graft branch copolymer / Rubber polymer) x 100 ...
It is a weight ratio.

The reduced viscosity (ηsp / c) of the acetone-soluble component is in the range of 0.45 to 1.0 dl / g. The reduced viscosity of the acetone-soluble component means that after the graft copolymer (2) was extracted with acetone, the acetone-soluble resin component was dissolved in N, N-dimethylformamide (DMF) at 30 ° C. to give a solution concentration of 0.4 g / Viscosity measured in dl. This value is 0.4
If it is less than 5 dl / g, sufficient impact strength cannot be obtained, and
If it exceeds 0 dl / g, the melt viscosity of the resin increases and the moldability decreases, which is not preferable.

In the thermoplastic resin composition of the present invention, the copolymerization composition ratio of the heat-resistant copolymer (a) and the graft copolymer (b) is (a) 30 to 80 parts by weight, (b) 70 to 20. Parts by weight, preferably (a) 35 to 70 parts by weight, (b) 6
5 to 30 parts by weight. Graft copolymer (D) is 70
When it exceeds the weight part, the rigidity of the resin decreases, which is not preferable.
If it is less than 20 parts by weight, sufficient impact strength cannot be obtained.

In the present invention, the impact strength can be further improved by using a bisamide compound in the obtained thermoplastic composition. The bisamide compound (c) is, as a specific example, a compound having a structure in which an aliphatic monocarboxylic acid amide having about 5 to 20 carbon atoms is bonded with an alkylene group having about 1 to 5 carbon atoms. Examples of the aliphatic monocarboxylic acid amide in this case include so-called fatty acid amides such as caprylic acid (C8), capric acid (C10),
Lauric acid (C12), myristic acid (C14), stearic acid (C18), oleic acid (C18), and other amides are typical. The bisamide compounds are methylene bis (C1) and ethylene bis (C2) compounds. This is a typical example. You may use these together. Preferred specific examples include methylene bis stearamide and ethylene bis stearamide. The addition amount of the bisamide compound is 0.0 with respect to 100 parts by weight of the total amount of the thermoplastic resin compositions (a) and (b) of the present invention.
1 to 5 parts by weight, particularly 0.1 to 3 parts by weight are preferred. If the amount added is less than 0.01 parts by weight, a sufficient effect of improving the impact strength cannot be obtained, and if it exceeds 5 parts by weight, the heat resistance of the resin is lowered, which is not preferable.

The resin composition of the present invention may further contain, if necessary, 10 to 70% by weight of a vinyl cyanide monomer (B), an aromatic vinyl monomer and / or an α, β-unsaturated carboxylic acid ester. 0 to 20 parts by weight of a copolymer obtained by copolymerizing 90 to 30% by weight of the system monomer (C) can be added.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and a generally known method can be adopted. That is, the heat-resistant copolymer and the graft copolymer are uniformly mixed in a pellet, powder, or piece state using a high-speed stirrer, and then melt-kneaded with a uniaxial or multiaxial extruder having sufficient kneading ability. Various methods such as a method and a method of melt-kneading using a Banbury mixer or a rubber roll machine can be adopted. In addition, if necessary, reinforcing agents such as pigments and dyes, glass fibers, metal fibers, metal flakes, carbon fibers, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, stabilizers, antistatic agents, and hardeners. A flame retardant or the like can be added.

[0034]

EXAMPLES In order to describe the present invention more specifically, examples and comparative examples will be described below, but these examples do not limit the present invention. Unless otherwise specified, (part) means part by weight and (%) means% by weight.

Each physical property was determined according to the following measuring methods.

Izod impact value: ASTM D256 (1
Bending elastic modulus: ASTM D790 (1/4 "thickness was used.) Drop weight impact value: JIS K7211 (2 mm thickness, φ)
40 mm was used. ) Heat distortion temperature: ASTM D648 (measured at a load of 1.82 MPa using a 1/4 "thick test piece.) Reference Example 1 (polymerization of heat-resistant copolymer (a)) 1-1: 50% styrene , Acrylonitrile 20%, N
-Heat-resistant copolymer (1-1) was prepared by emulsion-polymerizing 30% of phenylmaleimide. (Ηsp / c = 0.62dl /
g) 1-2: 45% styrene, 15% acrylonitrile, N
-Emulsion polymerization of 40% phenylmaleimide to prepare a heat resistant copolymer (1-2). (Ηsp / c = 0.57dl /
g) Reference Example 2 (Polymerization of Graft Copolymer (B)) 2-1: Polybutadiene Latex (Rubber Particle Diameter 0.2)
40 parts of a monomer mixture consisting of 65% styrene and 35% acrylonitrile was emulsion-polymerized in the presence of 60 parts (solid content) of 5 μ, gel content 80%. The obtained graft copolymer is coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to give a powdery graft copolymer (2-1).
Was prepared. (Graft ratio = 37%, ηsp / c = 0.71
dl / g) 2-2: polybutadiene latex (rubber particle diameter 0.2
40 parts of a monomer mixture consisting of 64% styrene and 36% acrylonitrile was emulsion-polymerized in the presence of 60 parts (converted to a solid content) (5 μ, gel content 80%). The resulting graft copolymer is coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to give a powdery graft copolymer (2-2).
Was prepared. (Graft ratio = 18%, ηsp / c = 0.65
dl / g) 2-3: polybutadiene latex (rubber particle size 0.2
40 parts of a monomer mixture consisting of 75% styrene and 25% acrylonitrile was emulsion-polymerized in the presence of 60 parts (solid content) of 5 μ, gel content 80%. The obtained graft copolymer is coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to give a powdery graft copolymer (2-3).
Was prepared. (Graft ratio = 39%, ηsp / c = 0.73
dl / g) 2-4: Polybutadiene latex (rubber particle diameter 0.2
40 parts of a monomer mixture consisting of 50% styrene and 50% acrylonitrile was emulsion polymerized in the presence of 60 parts (solid content) of 5 μm and a gel content of 80%. The resulting graft copolymer is coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to give a powdery graft copolymer (2-4).
Was prepared. (Graft ratio = 45%, ηsp / c = 0.69
dl / g) Reference Example 3 (Polymerization of copolymer) 3-1: 65% styrene and 35% acrylonitrile were suspension polymerized to prepare a bead-shaped copolymer.

Examples 1 to 5 The heat resistant copolymers (1-1 and 2) produced in the above Reference Example,
Graft copolymer (2-1 to 3), copolymer (3-1 to 1)
2) are kneaded in a Henschel mixer at the compounding ratios shown in Table 1, and then extruded at a temperature of 2 mm with a 40 mmφ extruder.
After extruding at 50 ° C. and pelletizing each, each pellet was subjected to injection molding under the conditions of a molding temperature of 260 ° C. and a mold temperature of 80 ° C. to prepare each test piece, and the physical properties thereof were evaluated. The results are shown in Table-1. These satisfy all the conditions of the present invention, and have excellent mechanical strength and drop weight impact strength.

Comparative Examples 1 to 4 The heat resistant copolymers (1-1 and 2) produced in the above Reference Example,
Graft copolymer (2-1 to 3), copolymer (3-1 to 1)
2) are kneaded in a Henschel mixer at the compounding ratios shown in Table 1, and then extruded at a temperature of 2 mm with a 40 mmφ extruder.
After extruding at 50 ° C. and pelletizing each, each pellet was subjected to injection molding under the conditions of a molding temperature of 260 ° C. and a mold temperature of 80 ° C. to prepare each test piece, and the physical properties thereof were evaluated. The results are shown in Table-1. In Comparative Example 1, the composition ratio satisfies the condition, but 2
-2 has a low grafting rate, so the falling weight impact value is low. In Comparative Examples 2 to 4, the formula (I) is not satisfied and the falling weight impact value is low.

[0039]

[Table 1]

[0040]

The thermoplastic resin composition of the present invention is a molded product having excellent heat resistance, impact resistance and mechanical properties by blending the maleimide copolymer (a) and the graft copolymer (b). Can be obtained. Further, the thermoplastic resin composition having various properties can be suitably used as a material for automobile interior parts, office supplies, parts for electric and electronic devices, and the like, and has a high industrial value.

It is possible to Further, the thermoplastic resin composition having various properties can be suitably used as a material for automobile interior parts, office supplies, parts for electric and electronic devices, and the like, and has a high industrial value.

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Claims (2)

[Claims] 1. An N-substituted maleimide monomer (A) 1-45.
% By weight, 5 to 40% by weight of vinyl cyanide monomer (B),
A heat-resistant co-polymer comprising 20 to 80% by weight of an aromatic vinyl monomer and / or an α, β-unsaturated carboxylic acid ester monomer (C) and having a reduced viscosity of 0.4 to 0.8 dl / g. In the presence of 30 to 80 parts by weight of the combined polymer (a) and 30 to 75 parts by weight of the rubbery polymer (D), 10 to 70% by weight of the vinyl cyanide monomer (B) and the aromatic vinyl monomer and / Alternatively, it is obtained by graft polymerizing 70 to 25 parts by weight of a monomer mixture consisting of 90 to 30% by weight of an α, β-unsaturated carboxylic acid ester monomer (C), and the component (B) is defined as x% by weight. When the component (A) of the heat resistant copolymer (a) is y% by weight and the component (B) is z% by weight, the composition difference (xz) of the component (B) is represented by the following formula (I). 0.35 x y ≤ (x-z) ≤ 0.90 x y (I) and the composition range is satisfied. Theft rate is 25
~ 70% range, the reduced viscosity of the acetone-soluble component is 0.4
A thermoplastic resin composition obtained by mixing 70 to 20 parts by weight of the graft copolymer (II), which is in the range of 5 to 1.0 dl / g. 2. A thermoplastic resin composition comprising 0.01 to 5 parts by weight of a bisamide compound (c) based on 100 parts by weight of (a) and (b).